AIM:To evaluate changes in the fatty acid composition of erythrocyte membrane phospholipids during severe and mild acute pancreatitis(AP)of alcoholic and nonalcoholic etiology.METHODS:All consecutive patients with a diagnosis of AP and onset of the disease within the last 72 h admitted to the Hospital of Lithuanian University of Health Sciences between June and December 2007 were included.According to the Acute Physiology and ChronicHealth Evaluation(APACHEⅡ)scale,the patients were subdivided into the mild(APACHEⅡscore<7,n=22)and severe(APACHEⅡscore≥7,n=17)AP groups.Healthy individuals(n=26)were enrolled as controls.Blood samples were collected from patients on admission to the hospital.Fatty acids(FAs)were extracted from erythrocyte phospholipids and expressed as percentages of the total FAs present in the chromatogram.The concentrations of superoxide dismutase and glutathione peroxidase were measured in erythrocytes.RESULTS:We found an increase in the percentages of saturated and monounsaturated FAs,a decrease in the percentages of total polyunsaturated FAs(PUFAs)and n-3 PUFAs in erythrocyte membrane phospholipids of AP patients compared with healthy controls.Palmitic(C16:0),palmitoleic(C16:1n7cis),arachidonic(C20:4n6),docosahexaenoic(DHA,C22:6n3),and docosapentaenoic(DPA,C22:5n3)acids were the major contributing factors.A decrease in the peroxidation and unsaturation indexes in AP patients as well as the severe and mild AP groups as compared with controls was observed.The concentrations of antioxidant enzymes in the mild AP group were lower than in the control group.In severe AP of nonalcoholic etiology,the percentages of arachidic(C20:0)and arachidonic(C20:4n6)acids were decreased as compared with the control group.The patients with mild AP of nonalcoholic etiology had the increased percentages of total saturated FAs and gama linoleic acid(C18:3n6)and the decreased percentages of elaidic(C18:1n9t),eicosapentaenoic acid(EPA,C20:5n3),DPA(C22:5n3),DHA(C22:6n3)as well as total and n-3 PUFAs in erythrocyte membrane phospholipids.CONCLUSION:The composition of FAs in erythrocyte membranes is altered during AP.These changes are likely to be associated with alcohol consumption,inflammatory processes,and oxidative stress. AIM: To evaluate changes in the fatty acid composition of erythrocyte membrane phospholipids during severe and mild acute pancreatitis (AP) of alcoholic and nonalcoholic etiology. METHODS: All consecutive patients with a diagnosis of AP and onset of the disease within the last 72 h admitted to the Hospital of Lithuanian University of Health Sciences between June and December 2007 were included. According to the Acute Physiology and Chronic Health Evaluation (APACHE II) scale, the patients were subdivided into the mild (APACHE II score <7, n = 22) and severe (APACHE II score ≥7, n = 17) AP groups. Healthy individuals (n = 26) were enrolled as controls. Blood samples were collected from patients on admission to the hospital. Fatty acids (FAs) were extracted from erythrocyte phospholipids and expressed as percentages of the total FAs present in the chromatogram. concentrations of superoxide dismutase and glutathione peroxidase were measured in erythrocytes .RESULTS: We found an increase in the percentages of saturated and monounsaturated FAs, a decrease in the percentages of total polyunsaturated FAs (PUFAs) and n-3 PUFAs in erythrocyte membrane phospholipids of AP patients with healthy controls. Palmitic (C16: 0n7cis), arachidonic : 4n6), docosahexaenoic (DHA, C22: 6n3), and docosapentaenoic (DPA, C22: 5n3) acids were the major contributing factors. A decrease in the peroxidation and unsaturation indexes in AP patients as well as the severe and mild AP groups as compared with controls was observed. The concentrations of antioxidant enzymes in the mild AP group were lower than in the control group. Severe AP of nonalcoholic etiology, the percentages of arachidic (C20: 0) and arachidonic (C20: 4n6) acids were decreased as compared with the control group. The patients with mild AP of nonalcoholic etiology had the increased percentages of total saturated FAs and gama linoleic acid (C18: 3n6) and the decreased percentages of elaidic (C18: ln9t), eicosapentaenoic acid (EPA, C20 : 5n3), DPA (C22: 5n3), DHA (C22: 6 n3) as well as total and n-3 PUFAs in erythrocyte membrane phospholipids. CONCLUSION: The composition of FAs in erythrocyte membranes is altered during AP. These changes are likely to be associated with alcohol consumption, inflammatory processes, and oxidative stress.